I have never tried clicker training, I've read stuff on it though, but never tried it. Where do I get the stuff for it? I'm desperate.

As for the harness, well right now I use the British Training Lead. If you don't know what that is, basically just a loop you put around the dogs neck, not attach to a collar and it gets tighter as they pull(sort of like a choker chain without the chain part). He just chokes himself though, he doesn't care. I have a harness, but it hasn't exactly helped at all.